A newly formed concrete slab needs to be shored for a comparatively short time, normally only a few days, while the drop beams normally need to be supported for a longer period, such as fourteen days. As a result, the forms for the concrete slab are often tied up for comparatively long periods of time.
As this type of construction is common and usually occurs in relatively large buildings, it is advantageous to shift the concrete forms from one area to another as soon after the pouring of the concrete as possible. The longer the forms have to remain in position supporting the concrete in one location, the greater the number of forms that must be available for the job. Therefore, if it is possible to move the slab forms without disturbing the beam forms from a given location in a relatively short time, the number of slab forms required can be reduced. This will be seen as an important economical factor when one realizes that the cost of the floor slabs is considerably greater than that of the drop beams.
Shoring towers or structures have been used for many years to support slab forms and drop beam forms. In the past, in order to remove the slab forms as soon as the slab was self-supporting, the upper end of the tower had to be loosened or taken down to release the slab forms. This also took the support off and released the beam forms. It was then necessary to retighten the existing support structure or build a new support to shore the beam for a further period. This system was costly and time-consuming, and it left the newly poured and relatively soft drop beams dangerously unsupported for a short time until they were shored up again and rarely reshored to the original tension.
The present invention overcomes these disadvantages by providing a support structure or tower that simultaneously and independently shores the slab forms and the associated beam forms. This support tower is constructed so that the slab forms can be easily released and removed without interfering with the support of the drop beam. In addition to this, each support tower or structure is of such light construction that it can be assembled in a horizontal position on the floor and then raised in ladder style to its vertical position, saving many hours of work. Although the tower is of simple and light construction, it is well braced, and the bracing and tower sections can be quickly assembled and disassembled. The tower or support structure may be made up of one or more similar tower sections surmounted one on the other, which sections may be of the same or different heights. In use, these sections can be quickly and easily interconnected, and braced by standard bracing extending between the sections to provide a very stable structure.
Therefore, a support structure according to one embodiment of the invention for simultaneously shoring up building forms at different levels is provided, and comprises at least one support section comprising a plurality of spaced pairs of vertical legs, the legs of each of said pairs being spaced apart on opposite sides of the support section, preferably by horizontal ledges extending between and secured to the legs of each pair of legs and supported by inclined cross-braces extending between and secured to the legs of one of said pairs and the adjacent legs of another of said pairs on the same side of the support section. In this embodiment, horizontal saddle beams may be secured at opposite ends to the legs of each said pairs near upper ends of the last mentioned legs to support at a first level a building form extending between these legs, and support members near ends of the saddle beams extending upwardly relative thereto to support a building form at a second level, said support members being movable away from the latter building form, and means may be provided for vertically adjusting the length of each leg.
In another embodiment, a support structure or tower in accordance with this embodiment of the invention, comprises at least one support section comprising a plurality of pairs of vertical legs, the legs of each of said pairs being spaced apart on opposite sides of the transverse section, preferably by ledgers extending between and secured to the legs of each pair of legs. The legs are also supported by inclined cross-braces extending between and secured to the legs of one of said pairs and the adjacent legs of another of said pairs of the same side of the two sections. Also in this embodiment, horizontal saddle beams are secured at opposite ends thereof to the legs of each said pairs near upper ends of the last mentioned legs to support at a first level a building form extending between these legs, said leg upper ends extending upwardly past the saddle beams to support a building form at a second level, and means are also provided for vertically adjusting the length of each of said legs.
Although these support structures may be used for supporting many things that need to be supported, they are particularly designed for supporting the forms for concrete slab floors and simultaneously supporting the forms for drop beams to be formed with the floors while the concrete for these is being poured, and shoring or supporting the slabs and beams until the concrete becomes self-supporting.
The horizontal saddle beams secured near upper ends of the legs comprise a pair of vertically spaced support surfaces preferably in the formed central web and a pair of flanges extending outwardly away from the central web proximate the top and bottom of the central web to form opposed ledges and a connector for securing the saddle beams to the legs, the connector being connected to the saddle beam supported by the spaced support surfaces and in one embodiment by a bracket (preferably secured to the web of the saddle beam) to abut the opposed ledges. Preferably, the brackets are each secured to a sleeve for securing to the legs and permitting the upper ends of the legs to telescopically extend past the saddle beam to support a building form at the second level. Also preferably, the saddle beam comprises a U-shaped channel at the top for carrying a wooden insert nailer.
Where the support structure carries two or more sections, the sections may be joined by pin means comprising two spaced arms as for example, U-shaped connector or security pins through aligned holes in the abutting legs of the joined sections and the internal or external coupling pins securing the legs of adjoining sections together. In this regard, the holes are so placed in the legs so that the spacing between the end aligned holes of the two vertically aligned legs of the section to be supported (including the vertical thickness of the collar of the coupling pin positioned between the legs) is equal to the distance between the arms of the U-shaped security pins. Holes are positioned through each of the legs at equal intervals starting from the end hole, corresponding to the distance between the arms. Preferably, one of the arms is longer than the other although both arms are sufficient in length to extend through the holes through the legs. Also preferably, the portion of the security pin connecting the arms is bent towards the extremities of the arm to act as a stop and limit penetration of the arms through the holes in the legs.
The means for vertically adjusting the length of the legs may comprise extnsion tubes internally extendable from the section legs. The extension tubes extending from the bottom of the support structure may be secured to screw jacks for sitting on earlier formed concrete slabs or timber sills. These extensions, as with the legs themselves, contain holes therethrough to permit passage of the U-arms of the securing pins therethrough. In the case of the extension tubes, half holes or semi-circular apertures may be formed at the very ends of the extension tube (in the case of the extension tube extending from the bottom of the section legs, the half holes is at the top of the extension tube, extending into the section leg; in the case of the extension tube extending from the top of the section legs, the half hole is at the bottom of the extension tube extending into the section leg) to ease and speed connection between the extensions and legs using the security pins having the two spaced arms.
Where the sections are to be secured to beams having T-shaped bolt slots in the base thereof, a plurality of bolts may be employed for securing in the T-shaped bolt receiving slots, each bolt comprising an elongated narrow head and stem, the head being of substantially the width of the bolt slot and having one set of diametrically opposite corners rounded, and the other pair of diametrically opposed corners square so that the bolt heads may enter the T-shaped slots anywhere along the beam slot and then by turning the bolt in one direction, the rounded corners permit the bolts to turn to a position across the slot whereat the square corners restrict the bolts from turning more than 180.degree. in the T-shaped slots. Fasteners are provided on the other end of the bolt for connecting to other components.
In one example, when the legs extend up past the saddle beam by means of extension tubes, a screw jack is fitted into the upper end of the extensions when extending from the extensions and means are provided (in one embodiment, a bearing plate) to support or carry beams having a T-shaped slot therein. For securing the beams to for example, the bearing plate, T-shaped bolts may be employed for securing in the T-shaped slots of the beams and means on the other for securing to the plate, each bolt comprising an elongated narrow head and stem, the head being of substantially the width of the beam slot and having one pair of diametrically opposite corners rounded, and the other pair of diametrically opposed corners square so that the bolt heads may enter the T-shaped slots anywhere along the beam slot and then by turning the bolt in one direction, the rounded corners permit the bolts to turn to a position across the slot whereat the square corners restrict the bolts from turning more than 180.degree. in the T-shaped slots. Fasteners are provided on the other end of the bolt for connecting to other components.